Interaction of CO molecules adsorbed on stepped platinum surfaces

Abstract
Recent reflection-absorption infrared data of CO adsorbed on Pt(533) and Pt(432) surfaces are explained by a calculation of normal modes based on a dipole coupling model. The model includes electronic polarizability and field-enhancement effects, and allows for the tilted orientation of CO molecules on step sites. The low-frequency band arises from one-dimensional arrays of CO molecules on step sites; the onset of the higher-frequency band signals a transition from one-dimensional to two-dimensional arrays of CO molecules.